Method of manufacture of smokeless powder



P nt r 1939 5 2,159,208

" D or-AE 0F SMOKELESS rownan Ellsworth S. Goodyear, Kenvil, N. 5., assignor to Hercules Powder Company, Wilmington, Del.,

a oorporationo! Delaware No Drawing. ApplicationAugust 24, 1937, Serial N0. 160,723

This invention relates to smokeless powder and tling action of low temperatures on the colloided method of manufacture thereof, and particudouble base smokeless powder in such ammunilarly to colloided double base smokeless powder tion. When the primer of a cartridge is fired, the and method of manufacture thereof. charge of smokeless powder in the cartridge re- Heretofore, in the manufacture of double base ceives a. severe shock and is projected violently 5 smokeless powder, it has been the practice to reagainst the base of the bullet, tending to break move water from the wet nitrocellulose employed. grains of powder which are' brittle. Broken by passing commercial, denatured ethyl alcohol grains of powder are necessarily of finer size than through a compressed cake of nitrocellulose, original grains, and broken grains consequently 1o usually forced through the nitrocellulose under 'bum faster and develop higher pressures in the 10 high pressure, in order to sweepthe water from gun. the nitrocellulose and replace the water with (18- I have found that this disadvantage of abnornatured ethyl alcohol, leaving the nitrocellulose mal rise in barrel pressures on firing at low wet with the denatured ethyl alcohol. temperatures can be almost completely avoided The cake of nitrocellulose is then broken up by the use of colloided double base smokeless 15 into'a fine powder, for example, by a suitable powders which have been colloided' by the use breaker, and mixed with nltroglycerine, acetone, of an anhydrous alcohol such as ethyl alcohol or and some more denatured ethyl alcohol, the iso-"propyl alcohol, in place of the same alcohols whole thoroughly mixed to start the colloiding heretofore used but containing substantial action, then pressed in a preliminary press to amounts of water, such as for example, 92% or 20 complete the colloiding of the nitrocellulose and 95% by weight of ethyl alcohol or 88% by weight form the colloid into large cylinders, which cylin-. of iso-propyl alcohol, and substantially anhyders are then put in a final pres and extruded drous acetone or ether, or mixtures thereof. I through a multiple orifice into strands, which am unable to explain definitely the reason for are then cut into by revolving knives, this improvement in the smokeless powders so 25 dried and glazed. produced, but believe that it is due to the pro- In place of the acetone, ether, or mixtures of duction of a tougher, less brittle colloid in my ether and acetone, have also been used. The deimproved powders. natured alcohol used heretofore in the operation As an example of my i proved P o and 39 referred to. above is known as 23 denatured ethyl. product, 77.25 parts by weight of nitrocellulose, alcohol, and contains one-half a gallon of bendry basis, and containing 13.22% nitrogen, and Z9118 3 1% o s f 92% by weight alcohol. ether-alcohol solubility of 30.75%, and containl'he acetone and ether heretofore used have been ing 15 parts by weight of anhydrous ethyl alcohol substantially anhydrous. (remaining in the nitrocellulose, for example,

3 In the case oi colloided double base smokeless from the dehydration of the nitrocellulose by anpowders prepared as descrimd above, and which hydrous ethyl alcohol) is thoroughly mixed with may contain, in addition to the nitrocellulose, 0.75 part by weight of diphenylamine, 1.5 parts various ingredients such as nitrcglycerine, diby weight of barium nitrate, 0.50 part by weight phenylamine, dimethyldlphenylurea, potassium of potassium nitrate, 22 parts by weight of anl0 nitrate, barium nitrate, and the like, it has-been hydrous acetone, and 20 parts by weight of nitro- 40 found that this use in firearms at low temperaglycerine in a covered mixer which may be wetures has resulted in the production of excessive tor-cooled, then further 'colloided by pressing in breech pressures. For example, in the firing oi a prelinunary press extruding from said prelimsuch colloided double base smokeless powders at 'inary press, pressed in a final press through a prevailing temperatures of l0 ht, many rifles 0&5" die having a. .010" pin into strands, the

, have burst. Tests of firing such rlfies loaded strands cut into grains (11 to the inch), the solwith such colloided double base smokeless powvent removed by airor water-drying, and ders at 40 have shown that the normal glazed. The finished powder when fired in a rifle breech pressure, shown at s temperatures at a temperature of 54 F. gives a breech presso and amounting to 40,05,0330 lbs. per square sure of about 1100 pounds per square inch more inch has been raised to the dangerous i- "rthan when fired at normal temperature, whereas 0155,00!) to 70,000 lbs, per sq. in. a smokeless powder made the same way by the While not capable of satisfactory proof, I atuse of ordinary ethyl alcohol gives a rise in prestribute this abnormalv rise in breech pressure sure of 5600 pounds pensquare inch.

so of guns fired at low temperatures to the embrit- As a further example of ny improved process" 55 parts of anhydrous ether and finished as in the above example. The finished powder when fired in a rifle at a temperature of about 58 F; gives a breech. pressure or about 9700 pounds per.

square inch higher than when fired at normal temperature, whereas a smokeless powder made in the same way with the use of ordinary ethyl alcohol gives a rise in pressure of 17,100 pounds per square inch.

As a further example of my improved process and product, 237.8 parts by weight of dry nitrocellulose is mixed with 2.20 parts by weight of symmetrical diethyldiphenylurea, 60 parts by weight of nitroglycerine, 40 parts by weight of anhydrous ethyl alcohol, 106 parts by weight of anhydrous ether, and parts by weight of anhydrous acetone. The powder is finished as in the above examples. The finished powder whenfired in a rifie at about -58 F. gives pressures about 13,800 pounds per square inch higher than when fired at normal temperatures, whereas a smokeless powder made in the same way with the use of ordinary ethyl alcohol gives a rise in pressure of 17,900 pounds per square inch at the same low temperatures.

As a further example of my improved process and product, 396 parts by weight of dry nitrocellulose is mixed-with 3.7 parts by weight of diphenylamine, parts by weight of a mixture of 55% nitroglycerinef'j and 25% ethylene glycol dinitrate and 20% diethylene glycol dinitrate, and 66 parts by weight of anhydrous ethyl alcohol and parts by weight of anhydrous acetone.

The powder is finished as in the above examples and coated with l of dinitrotoluene. The finished powder when fired in a rifle at a temperature of 58 F.,-gives a breech pressure of about 6200 pounds per square inch higher than when fired at normal temperature, whereas a smokeless powder made in the same way by the use of ordinary ethyl alcohol gives a rise in pres- Sure or 10,600 pounds per square inch when fired at the same low temperatures.

As a further example of my improved process and product, 337 parts byv weight of dry nitrocellulose containing 13.22% nitrogen, with an ether-alcohol solubility of 30.75%, is thoroughly mixed with 2.3 parts by weight of diphenylamine,

-60 parts by weight of nitroglycerlne, 70 parts by weight of anhydrous isopropyl alcohol and 68 parts by weight of anhydrous acetone. The

powder is then pressed into strands, granulated and finished as in the examples above. The finished powder when fired in a rifle at about gr'ains.

45 F. gives a breech pressure about 1800 pounds per square inch' higher than when fired ,at normal temperatures, whereas a smokeless powder made in the same way except that the iso-propyl alcohol used contained about 9.6% by weight of water, gives a breech pressure about 4600 pounds per square inch higher than when fired at normal temperatures.

It will be appreciated that my invention involves, broadly, the colloiding of nitrocellulose to form double base smokeless powders by the use of anhydrous mixtures of ethyl alcohol or of isopropyl alcohol and ethyl ether, or of the aforementioned alcohols and acetone, or of mixtures of the three, and the smokeless powder produced thereby, and that my invention is not limited to any particular type of colloided double base smokeless powder or any particular size and shape of-grain, and that my invention is not limited to the examples given. above. I

What I claim and desire to protect by Letters Patent is:

1 In the manufacture of colloided, double base smokeless powders, the step of colloiding nitrocellulose at ordinary temperatures by a mixture consisting of anhydrous solvents for. the nitrocellulose.

2. In the manufacture of colloided, double base smokeless powder, the step of colloiding nitrocellulose at ordinary temperature by a mixture consisting of anhydrous ethyl alcohol, anhydrous ethyl ether and an explosive .plasticizer.

3. In the manufacture of colloided, double base smokeless powder, the step of colloiding nitrocellulose at ordinary temperature by a mixture consisting of anhydrous ethyl alcohol, anhydrous acetone and an explosive plasticizer.

4. In the manufacture of colloided, double base smokeless powder, the step of colloiding nitrocellulose at ordinary temperature by a mixture consisting 0t anhydrous iso-propyl alcohol, anhydrous acetone and an explosive plasticizer.

5. Process of manufacture of double base smokeless powder consisting of admixing with nitrocellulose, nitroglycerine, a smokeless powder stabilizer, an inorganic nitrate, and an anhydrous mixture of ethyl alcohol and acetone, colloiding said mixture by kneading at ordinary temperatures, pressing said colloid into strands, cutting said strands into grains, and drying said grains.

6. Process of manufacture of double .base.

smokeless powder consisting of admixing with nitrocellulose, nitroglycerinea smokeless powder stabilizer, an inorganic nitrate, and ananhydrous mixture of, iso-propyl alcohol and acetone, colloiding said mixture by kneading at ordinary temperatures, pressing said-colloid into strands, cutting said strands into grains, and drying said Ems 'woR'rH s. GOODYEAR. 

